Field of the Invention
The present invention pertains generally to the field of dumping vehicles and wagons, and more particularly to dump wagons for agricultural and other uses in which it is necessary to provide a relatively high dumping position for the material container, while maintaining a relatively low transport position for the container.
The invention, still more particularly, relates to a vehicle with a hydraulic side dumping mechanism for dumping the contents of a container over a top side rail of the container. The vehicle is intended, for example, for the loading and unloading of sugar cane.
Dump vehicles for hauling and dumping bulk articles are widely used for agricultural purposes, wherein the vehicle often takes the form of a wagon adapted to be drawn behind a farm tractor. The wagon has a relatively tall sided material container, often having sloping sides so that all the material will pour out when the container is dumped. It is generally desirable in such wagons to provide a dumping mechanism so that when the container is dumped, the pouring edge along one side of the container will be elevated to a fairly high position to facilitate dumping sugar cane and the like into high sided trucks or trailers, railroad cars, or storage bins. At the same time, it is desirable to provide a relatively low transport position for the container so that the stability of the wagon as it moves over uneven ground will be improved, and so that no clearance problems are created by the wagon which would impair its usefulness in conjunction with other farm implements such as combines, and so that it is not too tall to fit into storage buildings.
The conflicting design requirements for a low transport height and a high dumping height have led to a number of prior art dumping wagons. U.S. Pat. No. 2,286,416 to Holmstrom and U.S. Pat. No. 2,812,210 to Osborn describe previously known dumping vehicles in which containers are pivotable about edges of the containers to dump the contents of the containers. Another prior art wagon is shown in U.S. Pat. No. 3,083,058 to Walstrom et al. This patent uses an upright slanting rail assembly and a first pair of hydraulic rams to move the container up the rail assembly to gain additional dumping height. A second pair of hydraulic cylinders dumps the elevated container. This structure, however, suffers from the disadvantages of requiring extra actuators, thereby increasing cost, and also from the disadvantage of requiring high vertical clearance for the rail assembly, even when the container is in its down position.
Another prior art approach to the problem is illustrated by U.S. Pat. No. 3,205,011, to Diem. In this structure, the gain in dumping height is achieved by rigidly affixing the material container on a pivot arm a distance from the pivot point of the arm. The distance away from the pivot point that the pouring edge is positioned equals the gain in dumping height as the pivot arm is rotated upward. A disadvantage of this structure is that if a significant height increase is to be achieved, the container must be displaced to the side of the wagon, thereby leading to either excessive width of the wagon or else reduced volume of the material container. Another disadvantage is that the center of gravity of the wagon is shifted toward one side during transportation, adversely affecting stability when the wagon is drawn over uneven ground.
Still another example of a prior art dumping wagon is illustrated by U.S. Pat. No. 3,830,543 to Kostman. This patent describes a transport vehicle which has the capability of attaining a high lift dumping position by use of a mechanical linkage in conjunction with a hydraulic actuator. During a dumping operation, the first movement of the vehicle's container is in a horizontal plane, the distance of which regulates the additional dumping height of the container above the vehicle, before the container pivots with respect to the vehicle. With the first movement of the container being in a horizontal plane, several problems are experienced. For instance, should an extremely high lift be required, there must be a limitation on the profile height of the tires of the unit so that the container can move above the tires to attain the desired dumping height. Additionally, should large diameter tires be required for floatation and support of the vehicle, the dumping container must be provided with a wheel well or fender which decreases its volume. Also, the track or center distance between the tires of the vehicle required by existing field row characteristics limits the versatility of the unit.
Another example of a prior art dumping wagon is shown in U.S. Pat No. 3,844,617 to Kostman. This patent describes a dumping vehicle having a high lift accomplished by the use of telescoping struts that support container pivots. When the struts are extended, the center of gravity of the container is moved towards the dumping side tires, which impairs the stability of the vehicle. In some instances, it is necessary to use stabilizing pads on the vehicle to prevent its overturning during a dumping operation.
In summary, some of the previously known vehicles have used four hydraulic cylinders, with two cylinders being used to raise the container and two cylinders being used to tilt and dump the container, while other previously known systems have used outrigger supports to prevent overturning of a vehicle during lifting and tilting of the vehicle's container.